1. Technical Field
This application relates to UMTS (Universal Mobile Telecommunications System) in general, and to an apparatus and method of handling simultaneous universal terrestrial radio access network radio resource control procedures which change the security configuration in a universal mobile telecommunications system user equipment in particular.
2. Description of the Related Art
UMTS is a third generation public land mobile telecommunication system. Various standardization bodies are known to publish and set standards for UMTS, each in their respective areas of competence. For instance, the 3GPP (Third Generation Partnership Project) has been known to publish and set standards for GSM (Global System for Mobile Communications) based UMTS, whereas and the 3GPP2 (Third Generation Partnership Project 2) has been known to publish and set standards for CDMA (Code Division Multiple Access) based UMTS. Within the scope of a particular standardization body, specific partners publish and set standards in their respective areas.
Standard document ETSI TS 125 331 v3.10.0 (2002 March) addresses the subject of UMTS RRC (Radio Resource Control) protocol requirements between UTRAN (Universal Terrestrial Radio Access Network) and UE (User Equipment). Although ETSI TS 125 331 specifies the requirement that the UE shall be able to process several RRC procedures, the document may not address how to meet the requirements for handling simultaneous RRC procedures in particular.
Consider a wireless mobile device (UE) that complies with the ETSI specifications for the UMTS protocol. The ETSI specification for the RRC layer of the UE ETSI TS 125 331 states in section 8 as quoted:
“The UE shall be able to process several simultaneous RRC procedures. After the reception of a message which invoked a procedure, the UE shall be prepared to receive and act on another message which may invoke a second procedure.”
Furthermore there are specific instructions with regard to handling RRC procedures simultaneously where more than one procedure requires a change to the security configuration. This is described in UMTS RRC protocol specification ETSI TS 125 331 v3.10.0 (2002 March), in sections: 8.6.3.4; 8.6.3.5; 8.1.12.4a; 8.2.2.12a; 8.3.1.9a; 8.3.3.5a; 8.3.4.5a and others.
These sections basically state that if any procedure is initiated which requires a change to the security configuration while there is already a procedure on going which also requires a change to the security configuration, then it should be rejected.
In short, it may only be possible to have one procedure that changes the security configuration on-going at a time.
It may not be possible to genuinely handle RRC procedures simultaneously without the use of multiple processors and so single processor implementations must be at least partially sequential. This makes it difficult to implement the above functionality such that the UE behaviour is consistent with handling messages simultaneously.